Pressure mat



Feb. 18, 1964 A k i R. HOPKINS PRESSURE MAT IN VEN TOR.

BY mfG/6MM A TTOPNE YS United States Patenty O 3,121,372 PRESSURE MAT Russell Hopkins, 1505 Callowhill St., Philadelphia, Pa. Filed Silly 14, 1961, Ser. No. 124,053 Claims. (Cl. 2-92) This invention relates to control mats and particularly to air pressure mats whereby approach of a person to a door or the like results in the application of their weight to the mat and development of air pressure therein sufiicient to actuate a switch and operate an automatic door opener. The present invention, however, relates only to the mat and is an improvement on the invention described and claimed in my Patent No. 2,858,394, dated October 28, 1958.

According to the present invention, a mat is formed of two sheets of exible material such as sheet rubber or rubber-like material, secured together at their peripheral edges to define a closed, sealed envelope. The edge of one of the sheets is thickened to form a flange-like structure extending completely around the edge of the sheet and the thickened portions at opposed edges of the mat are provided with an internal passage extending the length of the corresponding edge and defining two header chambers. A plurality of parallel flexible and air impervious tubes extend across the interior of the mat envelope with their opposite ends in communication with the two header chambers. One of the chambers is provided with a fitting to the exterior whereby pressure on any of the tubes result in development of an air pressure at the tting which may be utilized for operation of a pressure switch or similar device.

It is therefore an object of this invention to provide a novel control mat for controlling an automatic door opener or the like.

Another object of the invention is to provide such a control mat wherein the weight of a person approaching the door is detected by a multiplicity of flexible tubes dispersed throughout substantially the entire area of the mat, but wherein there are no bends in the tubes and wherein the structure lends itself to easy and rapid assembly.

Still another object of the invention is to provide a control mat of the type set forth that is economical and simple to make, yet efficient and reliable in operation.

Additional and further objects will become apparent to those skilled in the art as this description proceeds with reference to the accompanying drawings wherein:

FIG. 1 is a plan view of a mat embodying the present invention with a portion thereof broken away; and,

FIGS. 2 through 7 are enlarged vertical sectional views taken along correspondingly numbered lines in FIG. 1.

The control mat of the present invention comprises an assembly, shown herein in its preferred form, merely by way of example. The mat comprises a lower or bottom substantially flat sheet 2 which may be of rubber or similar material, with or without internal reinforcements, and an upper or tread sheet 4 of the same material. The upper or tread sheet 4 is formed with an enlarged edge portion defining a flange-like periphery 6. Having a surface 3 cemented, vulcanized or otherwise secured and sealed to the periphery of the bottom sheet 2. The upper and lower sheets thus form a fiat sealed envelope having spaced upper and lower walls. Opposed ends of the upper sheet 4 are further formed with a longitudinal groove or passageway 10 extending nearly the full length thereoic and one side of which is defined by the enlargement or flange-like portion 6. The other side of the groove 10 is defined in part by a rib 12 formed integral with the upper sheet 4 but which extends downwardly only about one half the distance between the sheets (see FIG. 6). The lower or step surface 3,121,372 Patented Feb. 18, 1964 ICC 14 0f the rib 12 is provided with spaced grooves 16 extending across its width, the grooves 16 being uniformly spaced and providing a multiplicity of seats for the ends of flexible tubes 18. A sealing strip 20 is provided with grooves 22 corresponding to the grooves 16 and positioned so that the grooves 22 embrace the other sides of the ends of tubes 18. The strip 20 is cemented, vulcanized or otherwise sealed and secured to the step surface 14 of rib 12 between tubes 18 and to the tubes themselves and since the tube ends are vulcanized or cemented within the grooves 16, a completely sealed connection between the interiors of the tubes 18 and the grooves 1i) is provided. The lowermost surface 24 of the strip 20 is cemented, vulcanized or otherwise sealed and secured to the upper surface of bottom sheet 2. The same structure as just described is present at both ends of the mat and it is to be noted that the tubes 18 extend completely across the interior of the envelope and are quite close together whereby they are dispersed over substantially the entire area of the mat so that a person stepping anywhere on the mat will apply pressure to the upper sheet 4 which exes downwardly and compresses a portion of a plurality of tubes 18 against the lower sheet 2 to build up air pressure in the closed header chambers or spaces defined by the grooves 10 and the interiors of the tubes 18.

One end of the mat is provided with an opening 26 (FIG. 4) through the flange-like portion 6 into communication with the groove 10 at that end of the mat. A suitable tubular fitting 28, which may be metallic tubing or rubber tubing, is sealed in the opening 26 and constitutes means for conducting pressure from the mat to a suitable pressure control switch or the like.

As will be apparent, the structure of the pressure mat described herein is extremely simple in construction, yet rugged and very easy to assemble. To effect assembly, the sheet 4 may be placed upside down on any suitable surface and the lengths of tubing 18 laid thereon with their ends nesting in grooves 16, after having applied appropriate cement to the grooves 16. Thereafter, the strip 20 is properly cemented and laid over the rib 12 with its grooves 22 embracing the exposed ends of the tubes 18. The strip 20 is of such length that its ends snuggly abut the inner-faces of the flange-like portions 6 at the opposite sides of the mat, as shown in FIG. 5. Thereafter, the bottom sheet 2 is placed in the illustrated position and suitably sealed to the upper sheet to complete the mat.

While a single specific embodiment of the invention has been shown and described herein, it is to be understood that the invention encompasses other forms, falling within the scope of the appended claims.

I claim:

1. In a control mat; superimposed top and bottom walls of flexible material secured together at their peripheral edges to deue a closed envelope; air impervious header means extending along at least one edge portion of said mat and between said top and bottom walls, said header means defining an elongated closed air chamber extending along a respective edge portion of said mat, a plurality of separate iiexible air impervious tubes extending across the interior of said envelope from said header means; each of said flexible tubes communicating with the air chamber of said header means whereby said tubes and header means sealingly enclose a body of air; and a conduit extending from the interior of said header means to provide a connection for connecting said mat to a pressure responsive device responsive to air pressure produced when a weight is placed on said mat.

2. A control mat as defined in claim 1 wherein said tubes are relatively closely spaced, extend generally parallel to each other and are dispersed throughout substantially the entire area of said mat.

3. A control mat as defined in claim 1 wherein said header means is positioned between edge portions of said top and bottom wallsand are sealingly joined thereto.

4. A control mat as dencd in claim 1 wherein said header means comprises a thickened edge portion of one of said walls, a groove extending alongsaid thickened edge portion, the other of said walls overlying and closing Said groove and being sealingly joined to said thickened edge portion to define, with said groove, said closed air chamber. Y

5. A control mat as defined in claim 4 wherein said thickened edge portion is provided with openings therein, generally parallel to said one wall and communicating with a side of said groove, the ends of said flexible tubes extending into said openings and being sealingly secured therein.

6. A control mat as defined in claim 5 wherein said openings are defined by secondary grooves in la step surface of said thickened portion, the ends of said tubes lying in said grooves, and a transversely grooved strip overlying said step surface and the said tube ends with its grooves embracing said tube ends and the portions between its grooves being sealingly secured to said step surface between said tube ends.

7. A control mat as defined in claim 1 wherein one of said walls is provided with a peripherally continuous thickened ange-like portion extending from one face thereof, the other of said walls having its entire periph- S' eral edge portion overlying and abutting the crest of said Harige-like portion and being sealingly secured thereto.

8. A control mat as defined in claim 7 wherein said header means is enclosed within said thickened angelike portion.

9. In a control mat; spaced walls of fiexible material secured together at their peripheral edges to define a closed generally fiat envelope; air impervious header means adjacent at least one edge portion of said mat, between said spaced walls, and defining a closed air chamber, a plurality of flexible air impervious tubes extending across the interior of said envelope from said header means; whereby said tubes and header means sealingly enclose a body of air; and a conduit extending from the interior of said header means to provide a connection for `connecting said mat to a pressure responsive device responsive to air pressure produced when a weight is placed on said mat.

10. A control mat as defined in claim 9 wherein said tubes are relatively closely spaced and are dispersed throughout substantially the entire area of said mat.

References Cited in the file of this patent UNITED STATES PATENTS 1,772,310 Hart Aug. 5, 1930 1,931,356 Porter Oct. 17, 1933 1,975,828 Conklin Oct. 9, 1934 2,372,218 Manson et al. Mar. 27, 1945 2,549,597 Harris et al. Apr. 17, 1951 2,858,394 Hopkins Oct. 28, 1958 

1. IN A CONTROL MAT; SUPERIMPOSED TOP AND BOTTOM WALLS OF FLEXIBLE MATERIAL SECURED TOGETHER AT THEIR PERIPHERAL EDGES TO DEFINE A CLOSED ENVELOPE; AIR IMPERVIOUS HEADER MEANS EXTENDING ALONG AT LEAST ONE EDGE PORTION OF SAID MAT AND BETWEEN SAID TOP AND BOTTOM WALLS, SAID HEADER MEANS DEFINING AN ELONGATED CLOSED AIR CHAMBER EXTENDING ALONG A RESPECTIVE EDGE PORTION OF SAID MAT, A PLURALITY OF SEPARATE FLEXIBLE AIR IMPERVIOUS TUBES EXTENDING ACROSS THE INTERIOR OF SAID ENVELOPE FROM SAID HEADER MEANS; EACH OF SAID FLEXIBLE TUBES COMMUNICATING WITH THE AIR CHAMBER OF SAID HEADER MEANS WHEREBY SAID TUBES AND HEADER MEANS SEALINGLY ENCLOSE A BODY OF AIR; AND A CONDUIT EXTENDING FROM THE INTERIOR OF SAID HEADER MEANS TO PROVIDE A CONNECTION FOR CONNECTING SAID MAT TO A PRESSURE RESPONSIVE DEVICE RESPONSIVE TO AIR PRESSURE PRODUCED WHEN A WEIGHT IS PLACED ON SAID MAT. 